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Infecting Pacific Herring with Ichthyophonus sp. in the laboratory

December 14, 2015

The protistan parasite Ichthyophonus sp. occurs in coastal populations of Pacific Herring Clupea pallasii throughout the northeast Pacific region, but the route(s) by which these planktivorous fish become infected is unknown. Several methods for establishing Ichthyophonus infections in laboratory challenges were examined. Infections were most effectively established after intraperitoneal (IP) injections with suspended parasite isolates from culture or after repeated feedings with infected fish tissues. Among groups that were offered the infected tissues, infection prevalence was greater after multiple feedings (65%) than after a single feeding (5%). Additionally, among groups that were exposed to parasite suspensions prepared from culture isolates, infection prevalence was greater after exposure by IP injection (74%) than after exposure via gastric intubation (12%); the flushing of parasite suspensions over the gills did not lead to infections in any of the experimental fish. Although the consumption of infected fish tissues is unlikely to be the primary route of Ichthyophonus sp. transmission in wild populations of Pacific Herring, this route may contribute to abnormally high infection prevalence in areas where juveniles have access to infected offal.

Publication Year 2015
Title Infecting Pacific Herring with Ichthyophonus sp. in the laboratory
DOI 10.1080/08997659.2015.1095809
Authors Paul Hershberger, Lucas Hart, Ashley MacKenzie, M.L. Yanney, Carla M. Conway, Diane G. Elliott
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Aquatic Animal Health
Index ID 70160545
Record Source USGS Publications Warehouse
USGS Organization Western Fisheries Research Center